[1] Univ Mohammed V Rabat, Fac Sci, ESMAR, Equipe Sci Matiere & Rayonnement, Rabat, Morocco
[2] Univ Ibn Tofail Kenitra, Fac Sci, LabSIMO, Dept Phys, Kenitra, Morocco
[3] Univ Moulay Ismail, Fac Sci & Tech Errachidia, Errachidia, Morocco
[4] Univ Zaragoza, Dept Fis Teor, E-50009 Zaragoza, Spain